Question: What is the significance of having a densitometer at the press?

Answer: Books have been written about densitometry, so I'll deal with just one of the benefits of using this device to "read" reflected light. Different individuals see color differently. (Incidentally, that's also true of black.) Men are about eight times more likely to be born with some impaired ability to discern color than are women. Men's color acuity begins to degrade in middle age - and it continues to decline for the rest of their lives.

That's not the case with women. If a female looks at the same press sheet as a 50-year-old male press operator, most likely she sees the image differently - and more accurately. Densitometry overcomes color-perception problems associated with the human aging process by providing electronic readings that ensure accuracy.

It is especially important that densitometer readings be taken and recorded if a job is on press for more than one shift. This is essential because when press operators depend entirely on the human eye to read color, a second-shift operator will frequently "tweak" the color run by his first-shift counterpart. The result: color variation. Densitometry depends on color bars that are plotted on the sheet.

It's important that you tell your printer if a job may rerun. That should serve as a signal to the printer to take and record densitometry readings to ensure color consistency.